Other kinds of extensional flows

Apart from the uniaxial extensional flow considered above, there are two other kinds of flows where the material is stretched, see figure 25. 

These two kinds of extensional flows are less demanding on microstructures such as individual polymer chains, since uniaxial extension demands that a three-dimensionally random chain be pulled towards a straight extended chain. 

All these extensional flows have different values of viscosity associated with them, so that in the simplest case for Newtonian flquids - or for all liquids at low enough shear/ extension rates - which are as follows 

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